Mercedes-Benz Q&A

1990 Mercedes-Benz 350SDL Question: Door lock is jammed.

Driver side door lock is jammed so that the key won't turn, lock or unlock. The lock itself works when locking from the passenger door. Tried jiggling, but no effect. Anybody else have this problem? Thanks!

Try lubricating the lock with a penetrating oil like Liquid Wrench. Don't use WD-40 because it's no good in locks, it dries to a waxy substance which is good for rust prevention but it's not really a lubricant, and after a while, it'll gum up a lock. That's my personal painful experience talking...
If that's no good, you may need to replace the lock. Get a locksmith to re-key the lock so you can use the original key.